Firefox blocks Adobe Flash NPAPI plugin for 11.2.202.481 and earlier

Several serious security vulnerabilities were found in Adobe's flash plugin with exploits known to be in the wild. Because of the critical nature of the vulnerabilities, the Mozilla foundation decided to block this version of the plugin. Unfortunately, at the time of the blocklist, only the PPAPI version of the plugin (as used by chromium) was available and Firefox users found the NPAPI plugin was blocked via Firefox's click-through security mechanism.

UPDATE: As of 2015/07/16, Adobe released 11.2.202.491 which fixes all known issues for PPAPI and NPAPI and updates are available for Ubuntu